What the hell is this?!?!!!

I can't figure this out. This is now affecting a few of my plants. Soil feels cold. I'm stuck at phosphorus lockout from cold. Since new growth seems to be stunted I'm concerned. pH has also dropped to 5.8 in FFOF in this single container would this cause the discoloration I am seeing. This is the clearest I've ever seen the problem on any of my plants and last night was the coldest night we've had this year hence the cold theory. Plants are in the closet which gets a slight draft at night from cracks in the old horsehair however not so to affect the rest of our house. Thanks in advance.

Did this problem start with just 1 plant rather did you first notice it on just 1? Have you brought new clones into you house lately or are these from seed? Do you own a scope? It's looking like it could be broad mites that is why I ask.

It started with the seedlings. Then it went away. Now it is in most plants to some degree. This one is the clearest view but noe of them are nearly this dark. I really am concerned it is due to cold weather but I can't find anyone who has had similar problems due to cold weather in VEG. I know you can bring out crazy colors with cold temps but I need to be sure. I thought at first that it could be fungus gnat larvae but I'm not seeing any bugs or mites crawling around anywhere. I'm positive it is not a pest issue. I'm really just hoping someone has had plants look exactly like this and can tell me how it went for them.

I'd like to know too. Been having some of the same problems since the temp dropped. I use Gnatrol and haven't seen any gnats either. Also been flushing every week since I noticed the yellowing and it's really seemed to help, but I've always used 5.8 PH (years now), so I don't think that's your problem? Then again, I'm using a new soil mix and we're having some of the same symptoms...

How cold has it gotten? I started noticing problems when the temps were around 50F in the grow room.

i think the soil is getting to cold..... when lights go out..... then come on huge temp change, sounds to huge of a temp change,....

Pretty sure it was a cold issue. I spent a lot of time researching it. I ended up deciding that it was a result of my 14/10 light schedule and cooler than ambient temperature soil. It's great though because the environment is even more like spring time. Just found out we're having two girls so far. Hoping for more!! 25 days from sprout to pistils. Next time I'll try 12/12 springtime light schedule see If I can get them to mature even faster as per many grow resource recommendations. I found a link to explain it if you're interested. Same thing that happens when growers put bud in the fridge or outdoors it goes through a cold spell. Spring time has warm days and cooler nights. I added insulation and turned off one of my fans leaving on only the most powerful bypass exhaust. Problem looks to be clearing up. First photo is my lady up close showing you her parts (not the stipules) (completely inappropriate haha) and the next two are side by sides of her showing the recovery she made form yesterday morning to earlier today when I took it.
http://dnr.wi.gov/eek/veg/trees/treestruecolor.htm

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Gotta be, I just moved out of the cold basement/garage myself. The plants have perked up since. Checked them last night and they're definitely growing again. I didn't have any problems budding during the cold a month or so ago, though. Decent enough yield, and I found out I was growing something with purple genetics. Gotta love nature sometimes.




Looks like your ladies are on the way to being some nice bushes. I wish you luck in your sexing.